I had a great time with the SK challenge, so I jumped out of my seat once I saw this challenge. Now that I'm looking a bit further though, it doesn't seem to be worth it. The killer is not only how departure airports don't count, but primarily because the B6 network is purely hub and spoke while also not being nearly at the scale of legacies. If it was WN running this, we could easily hit up a few cities in a day, but with these B6 rules essentially forcing us to fly a bunch of return legs, the reward just isn't enough.